12 water pumps can make a water tank empty in 20 minutes. But 2 pumps are out of order. How long will the remaining pumps take to make the tank empty?
12 water pumps can make a water tank empty in 20 minutes. But 2 pumps are out of order. How long will the remaining pumps take to make the tank empty?
Explanation
Since 12 pumps can empty the tank in 20 minutes, the rate at which they empty the tank is 1 tank / 20 minutes.
With 2 pumps out of order, we have 12 - 2 = 10 pumps left. Since the rate is directly proportional to the number of pumps, the rate of the remaining 10 pumps is:
10/12 × (1 tank / 20 minutes) = 1 tank / 24 minutes
So, the remaining 10 pumps will take 24 minutes to empty the tank.